The present invention relates to a journal made of sintered alloy and assembled to a rotary shaft for frictional engagement with a journal bearing to support the rotary shaft.
The journals are secured to a shaft loaded with many members and frictionally supported by respective journal bearings. Thus the journals are required to be highly wear-resistant and well lubricated. Accordingly journals are made of a sintered alloy which is superior in wear-resistance and lubricating ability.
Journals of sintered alloys have conventionally been secured to a rotary shaft of cast iron or steel pipe by means of screws. Brazing and welding are unavailable for joining journals made of sintered alloys with a rotary shaft. The reason for this is that joining by brazing is not durable under severe working conditions and welding can not prevent the porous sintered alloy from developing excessive blow holes and cracks.
It has been proposed to make journals of a shrinkable sintered alloy or a liquid phase sintered alloy which can be metallurgically bonded on a shaft due to diffusion. However, a shrinkable or liquid phase sintered alloy is not very porous or oily, and therefore is not suitable for use as a slidable part subjected to a relatively high plane pressure. The known journals made of a sintered alloy is composed of a pair of semicircular parts which are mounted on a rotary shaft and fastened together by screws, thus the expensive machining and assembling cannot be eliminated.